The use of fuel pump modules to pump fuel from fuel tanks is well known in the automotive industry. A typical fuel pump module may include, for example, a fuel reservoir, a fuel pump within the fuel reservoir, a fuel level sensor, one or more filters positioned upstream of the pump inlet, an in-line fuel filter positioned downstream of the pump outlet, and a pressure regulator. The fuel pump module typically rests on the bottom of the fuel tank and pumps fuel from the tank until the tank is substantially empty.
During operation of the fuel pump, the reservoir is continually being filled to ensure that a steady supply of fuel is available to the fuel pump at all times during operation of the pump. Normally, fuel is drawn into the reservoir from the fuel tank by the fuel pump. In the case that the fuel level in the fuel tank is low, or vehicle maneuvering causes the fuel to slosh inside the fuel tank such that the fuel pump inlet cannot draw fuel from the bottom of the tank, the fuel pump is able to draw fuel from within the reservoir. This allows for substantially uninterrupted operation of the fuel pump, in that the fuel pump is substantially prevented from “running dry” and causing unwanted cycling of the fuel pressure to the engine.
Conventional fuel pump modules typically utilize a valve assembly, sometimes referred to as a discriminator valve, that is designed, in part, to prevent the fuel accumulated in the reservoir from draining back into the fuel tank when the fuel pump is not operating. A conventional fuel pump module, having a conventional discriminator valve, is shown and described in more detail below.